yahoo-eng-team team mailing list archive

[Julian Andres Klode <1794982@xxxxxxxxxxxxxxxxxx>]

Public bug reported:

/etc/apt/apt.conf.d/90cloud-init-pipelining disables pipelining which
causes a significant performance reduction in apt downloads. This should
not be necessary in 16.04, as apt can detect broken pipeline responses,
fix it, and disable pipelining for the next connection (it can also
match the response based on the hashes, rather than just complaining the
hashes are wrong).

This is causing a significant performance decrease, as a small sample,
firefox in a fresh lxd container:

without pipelining: Fetched 81.1 MB in 6s (13.2 MB/s)
with pipelining: Fetched 81.1 MB in 2s (32.2 MB/s)

(400 Mbit/s connection, 25-30ms RTT, xenial LXD container)

** Affects: cloud-init
     Importance: Undecided
         Status: New

** Description changed:

  /etc/apt/apt.conf.d/90cloud-init-pipelining disables pipelining which
  causes a significant performance reduction in apt downloads. This should
  not be necessary in 16.04, as apt can detect broken pipeline responses,
  fix it, and disable pipelining for the next connection (it can also
  match the response based on the hashes, rather than just complaining the
  hashes are wrong).
  
  This is causing a significant performance decrease, as a small sample,
  firefox in a fresh lxd container:
  
- without pipelining: Fetched 81.1 MB in 6s (13.2 MB/s)                                                                                                            
- with pipelining: Fetched 81.1 MB in 2s (32.2 MB/s)          
+ without pipelining: Fetched 81.1 MB in 6s (13.2 MB/s)
+ with pipelining: Fetched 81.1 MB in 2s (32.2 MB/s)
  
- (400 Mbit/s connection, 25-30ms RTT)
+ (400 Mbit/s connection, 25-30ms RTT, xenial LXD container)

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https://bugs.launchpad.net/bugs/1794982

Title:
  drop /etc/apt/apt.conf.d/90cloud-init-pipelining in 16.04+

Status in cloud-init:
  New

Bug description:
  /etc/apt/apt.conf.d/90cloud-init-pipelining disables pipelining which
  causes a significant performance reduction in apt downloads. This
  should not be necessary in 16.04, as apt can detect broken pipeline
  responses, fix it, and disable pipelining for the next connection (it
  can also match the response based on the hashes, rather than just
  complaining the hashes are wrong).

  This is causing a significant performance decrease, as a small sample,
  firefox in a fresh lxd container:

  without pipelining: Fetched 81.1 MB in 6s (13.2 MB/s)
  with pipelining: Fetched 81.1 MB in 2s (32.2 MB/s)

  (400 Mbit/s connection, 25-30ms RTT, xenial LXD container)

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